judo-runtimevalidation-rules

name: judo-runtime:validation-rules description: Configure and debug JUDO validation rules. Use when troubleshooting validation failures, understanding constraint enforcement, or configuring validation behavior. metadata: author: BlackBelt Technology version: "${project.version}"

Validation Rules

Guide for configuring and debugging JUDO validation rules.

Validation Flow

sequenceDiagram
    participant App as Application
    participant DPV as DefaultPayloadValidator
    participant VP as ValidatorProvider
    participant Val as Validators
    participant Res as ValidationResult
    
    App->>DPV: validatePayload(payload)
    DPV->>DPV: Traverse attributes
    loop For each attribute
        DPV->>VP: getValidators()
        VP-->>DPV: List<Validator>
        loop For each validator
            DPV->>Val: isApplicable(feature)?
            Val-->>DPV: true/false
            opt If applicable
                DPV->>Val: validateValue(...)
                Val-->>DPV: ValidationResult[]
            end
        end
    end
    DPV-->>App: All results

Built-in Validators

Validator	Constraint	Applies To
`MaxLengthValidator`	`maxLength`	String attributes
`MinLengthValidator`	`minLength`	String attributes
`PatternValidator`	`pattern` (regex)	String attributes
`PrecisionValidator`	`precision`, `scale`	Numeric attributes
`RangeValidator`	Range-of references	Embedded references
`UniqueAttributeValidator`	Identifier uniqueness	Identifier attributes

Constraint Annotations

Constraints are defined in the ASM metamodel:

// Check constraints on an attribute
List<EAnnotation> constraints = AsmUtils
    .getExtensionAnnotationListByName(attribute, "constraints");

constraints.forEach(constraint -> {
    constraint.getDetails().forEach((key, value) -> {
        System.out.println(key + " = " + value);
    });
});

Example Constraints

@constraints(maxLength = 100)
String name;

@constraints(pattern = "^[A-Z]{2}[0-9]{6}$")
String accountNumber;

@constraints(precision = 10, scale = 2)
Decimal price;

Validation Context Options

Control validation behavior:

Map<String, Object> context = new HashMap<>();

// Validate required fields (default: true)
context.put(DefaultPayloadValidator.VALIDATE_MISSING_FEATURES_KEY, true);

// Skip invalid value validation (default: false)
context.put(DefaultPayloadValidator.IGNORE_INVALID_VALUES_KEY, false);

// Mark as create operation (affects derived references)
context.put(DefaultPayloadValidator.VALIDATE_FOR_CREATE_OR_UPDATE_KEY, true);

// Skip nested object traversal
context.put(DefaultPayloadValidator.NO_TRAVERSE_KEY, true);

List<ValidationResult> results = validator.validatePayload(
    eClass, payload, context, false
);

Debugging Validation

Enable Logging

<logger name="hu.blackbelt.judo.runtime.core.validator" level="DEBUG"/>

Issue 1: Validation Passes But Shouldn't

Checklist:

Is validator registered?

validatorProvider.getValidators().forEach(v -> 
    log.debug("Registered: {}", v.getClass().getName())
);

Is isApplicable() returning true?

validators.stream()
    .filter(v -> v.isApplicable(feature))
    .forEach(v -> log.debug("Applicable: {}", v.getClass().getName()));

Are constraints present in metamodel?

AsmUtils.getExtensionAnnotationListByName(feature, "constraints")
    .forEach(a -> log.debug("Constraint: {}", a.getDetails()));

Issue 2: Nested Validation Errors

Check the location in the error:

results.forEach(r -> {
    log.error("Location: {}", r.getLocation());
    log.error("Code: {}", r.getCode());
    log.error("Details: {}", r.getDetails());
});

Location format: orders[0]/items[2].price

Issue 3: Precision Validation Fails Unexpectedly

The PrecisionValidator counts significant digits:

// 123.45 has precision 5 (not 3)
BigDecimal value = new BigDecimal("123.45");
log.debug("Precision: {}", value.precision());  // 5
log.debug("Scale: {}", value.scale());          // 2

Validation Results

classDiagram
    class ValidationResult {
        +String code
        +String location
        +Map details
    }
    class ValidationException {
        +Collection~ValidationResult~ validationResults
    }
    ValidationException o-- ValidationResult

Handling Results

try {
    validator.validatePayload(eClass, payload, context, true);
} catch (ValidationException e) {
    e.getValidationResults().forEach(result -> {
        switch (result.getCode()) {
            case Validator.ERROR_MISSING_REQUIRED_ATTRIBUTE:
                handleMissingField(result);
                break;
            case Validator.ERROR_MAX_LENGTH_VALIDATION_FAILED:
                handleMaxLength(result);
                break;
            default:
                handleGenericError(result);
        }
    });
}

Required String Handling

Control empty string validation:

// Accept empty strings as valid for required fields
validator.setRequiredStringValidatorOption(
    RequiredStringValidatorOption.ACCEPT_EMPTY
);

// Require non-empty strings (default)
validator.setRequiredStringValidatorOption(
    RequiredStringValidatorOption.ACCEPT_NON_EMPTY
);